Color degradation in Snagit capture (Snagit Version 2018.2.3 on Mac)

When I use Snagit to screen capture, it darkens the colors of the image so the screenshot is not representative of the original. I have Snagit Version 2018.2.3 and macOS High Sierra 10.13.6. This has been going on for at least the last year. I have not noticed it in versions before 2018.